CIG launches new tool and webinar for climate-smart stormwater design

The UW Climate Impacts Group has released an online tool to help stormwater and wastewater managers in the Northwest design and operate with climate change in mind. Developed in collaboration with the City of Portland, City of Gresham and Clackamas County, all in Oregon — and building on previous collaborations in Washington State — the tool provides new localized projections of changing heavy rain events through the end of the 21st century.

Interested in learning more about how to use the tool? Join UW Climate Impacts Group scientists Harriet Morgan and Guillaume Mauger and King County’s Bob Swarner for an informational webinar in May. Morgan and Mauger will provide an introduction to the tool, and Swarner will describe how King County is using the projections in wastewater planning.

Check out the tool

Read the project page

Thursday, May 20, 2021
4-5 p.m.


Most stormwater and wastewater systems are designed based on the assumption that heavy precipitation events are static or unchanging. Yet recent research has shown that Pacific Northwest rainstorms are projected to become more intense with climate change. Projected changes in heavy precipitation events could strain our stormwater and wastewater systems.

To help stormwater managers meet this challenge, climate researchers at the UW Climate Impacts Group and officials in local and city government in Oregon collaborated to develop a tool that will guide the design and operation of 21st century stormwater management systems. Users can hone in on the precipitation frequencies and durations that are most relevant to their specific needs, and results and graphics can be downloaded for later use. Some broad take-aways from the new projections:

  • Extreme events are projected to get larger nearly everywhere in the Northwest, with the largest changes expected in some of the wettest parts of the region (high elevations and windward slopes)
  • Shorter (e.g., one hour) precipitation durations show larger changes than longer (e.g. 48 or 72 hour) durations.

This project builds on collaborations between the UW Climate Impacts Group and local governments in Washington State, including: King and Thurston Counties, the City of Everett, and the Port Gamble S’Klallam Tribe. The tool shows precipitation data for Washington, Oregon, Idaho, and parts of British Columbia, California, Montana and more.

Check out the tool 

Register for the webinar